I suspect she kind of broke from pressure. She was playing as Robin Hood, but she had moral qualms about it all. Because of that, she was already burdened about whether what she was doing was right or wrong. Add Meifa being an amoral, badly nurtured witch with insane powers, who was the center of many bad things that happened around Chloe that Chloe felt responsible for, she probably shattered and Meifa ended up as the new building base she centered herself around. She knew that helping this broken bird of a witch live a normal life without using her absolutely insane powers to kill people was definitely Good without a reasonable doubt in her mind and viewed it as her only lifeline to atone for her years of guiltily robbing people for the good of others.